Models and Reasoning Effort
Choose which AI model answers in a chat, and how long it thinks before it answers.
What it is
Every chat uses one language model (LLM), shown with the effort at the bottom right of the input box. Cowork offers Micromeet models as soon as you sign in, and can also use your own ChatGPT (Codex) or Claude account. Pictures use a separate Image model.
When to use it
| Change the model or effort when | Keep the default when |
|---|---|
| A job needs careful reasoning, such as a long analysis | Everyday tasks: summaries, tables, emails |
| You want quicker answers for simple work | You are not sure; the default is chosen for most work |
| You want to use your own Claude or ChatGPT subscription |
How to use it
- Click the model name at the bottom right of the input box to open Models.
- Under LLM, click a model for this chat. Use the search icon to find one by name.
- Under Image, choose the model for pictures; this applies to All chats.
- Next to the model, choose the effort: Low, Medium, High, Max or Default, depending on the model. Higher effort thinks longer and answers more slowly.
- For Codex or Claude, sign in when asked: a Login button appears next to it, or sign in under Settings › General › Models. The gear icon (Model settings) opens that page.
Example
You ask for a quarterly sales analysis across several spreadsheets. Before sending, you switch this chat to a stronger model and set the effort to High. The answer takes longer but works through every sheet. For the next chat, a quick email draft, the default is enough.
Limits and permissions
- Each chat keeps its own model; changing it in one chat does not change the others.
- The image model applies to all chats.
- Codex and Claude use your own account and its limits.
- You can change the model while the AI is working: the current answer finishes on the old model, and the next step uses the new one.
If something goes wrong
| What you see | What to do |
|---|---|
| The chat says your Codex or Claude session expired | Sign in again under Settings › General › Models |
| A model you expect is not in the list | Use the search icon; if it is still missing, it is not available to your account |
| Answers are too slow | Lower the effort, or choose a faster model for this chat |
Related
- Conversations and History Each chat keeps its own model
- Image Generation Make pictures with the image model
- Sign-in Problems Signing in to Claude or Codex